One of the most memorable sports moments occurred before Game 7 of the NBA Finals as an injured Willis Reed emerged onto the Madison Square Garden floor shortly before tip-off. Although he only played a few minutes, the rejuvenated Knicks beat the Lakers 113–99 to win the championship.

This was the final season of the two-division format in the NBA, before the Eastern and Western Divisions were divided into the Eastern and Western Conferences, with each conference having two divisions.

The 1969–70 season saw the NBA into a new decade as well as a new era. The retirement of Bill Russell from the Celtics at the end of the 1968–69 season effectively signaled the end of the Celtics dynasty that had dominated the NBA for the past decade.

The New York Knickerbockers were the top team in the league. The Knicks, as they were well-known, had a solid team of players led by star center Willis Reed and rising star guard Walt Frazier. Dave DeBusschere, who had been acquired from the Detroit Pistons the previous year, combined with Frazier and Reed to anchor the league's best defense. Coach Red Holzman led the club to wins in 60 of its 82 regular season games to top the league.

In just their second season in the league Milwaukee Bucks totaled 56 wins behind rookie superstar Lew Alcindor. The 7'2 230-pound center had caused controversy in boycotting the 1968 Summer Olympics, urging Elvin Hayes, Wes Unseld and Bob Lanier to do the same. The Bucks, however, were happy to sign him after a bidding war with the ABA. The rookie averaged 29 points per game on 52% shooting. He was also third in rebounds, seventh in shooting accuracy, second in minutes played, and blocked more shots than any center since Russell or Chamberlain, making him a strong MVP candidate in just his first year. Coach Larry Costello's team also had a strong backcourt of Jon McGlocklin and Flynn Robinson, and two ex-Cincinnati Royals, but Alcindor's arrival on the team nearly doubled their win total from the previous season, earning him rookie of the year honors.

The Baltimore Bullets also reached the 50-win plateau. Coach Gene Shue led a squad looking to improve after their early playoff exit the previous year. Guards Earl Monroe and Kevin Loughery were the team's main scoring threats, while center Wes Unseld and forward Gus Johnson excelled at rebounding, giving the Bullets more field goals than any other NBA team that year.

The Atlanta Hawks won the NBA's West Division title with 48 wins. The Hawks and coach Rich Guerin fielded a solid starting five, led again by scorer Lou Hudson. A early season trade with Detroit, netted star center Walt Bellamy. The Hawks again eyed a shot at the NBA Finals with some of the same faces from their St. Louis days.

Right behind the Hawks at 46 wins were the Los Angeles Lakers. The Lakers starting five had to account early for an injury to Wilt Chamberlain, who played just twelve regular-season games. Happy Hairston joined Elgin Baylor to average 20 points per game, even as Elgin was hampered by injury for much of the year. Guard Jerry West led the NBA in scoring, averaging 31.2 points per game on 50% shooting from the field and 82% from the free throw line. He also added 7.5 assists and solid defense in the backcourt yet again.

Only one other team, the declining Philadelphia 76ers of Billy Cunningham and Hal Greer had a winning record that year, for a total of just 6 out of the NBA's 14. This was down two teams from a year ago and represented a balancing out of talent as the have-not expansion teams began to acquire talent. The best example of this was Alcindor.

The Cincinnati Royals and Boston Celtics both fell far this year. Cincinnati hired former hated rival Bob Cousy as coach, and he jettisoned Ohio's most famous player, Jerry Lucas, to San Francisco. He also attempted to trade Oscar Robertson and then placed Robertson, the NBA's all-time passing guard, at shooting guard. The Royals went on to only win 36 games and miss the playoffs. After the retirement of Bill Russell, the defending NBA champion Celtics only won 34 games and finished second to last in the Eastern Division.

The top four teams from each division made the playoffs. Unusually, The NBA had the division winners face the third-best teams, while the second-seeds faced the fourth seeded teams in Round One. New York met third-place Baltimore in a rematch of the previous year's playoff series. The Knicks won the series in 7 games, including an overtime win in Game 1. The Bullets scoring was neutralized by the defensive-minded Knicks team. Milwaukee eliminated the 76ers in 5 games on the strength of Alcindor at center.

Atlanta's strong five, with player/coach Guerin coming off the bench effectively at age 37, beat the Chicago Bulls, led by ex-76er Chet Walker four games to one in the Western division semifinals. The Lakers survived a seven-game series with the second-year Phoenix Suns. The Suns had a strong frontline led by Paul Silas and former ABA star Connie Hawkins. The Suns also had solid guards in Dick Van Arsdale and Gail Goodrich, but had no answer for Chamberlain in game seven.

With the top seeds in both divisions advancing, New York then met Milwaukee while Atlanta met Los Angeles. The Lakers swept the Hawks in four games. Jerry West and Wilt Chamberlain were again on a mission, but the Lakers bench may have been the deciding factor in this series. In the East, New York eliminated the Bucks in five games. The Knicks guarded Alcindor's teammates, while Willis Reed challenged the young superstar.

The NBA now had a classic New York versus Los Angeles championship series that delighted league management. New York had the first two games at home at Madison Square Garden, winning Game 1. The Lakers evened the series, winning Game 2 105–103. Games 3 and 4 were in Los Angeles, and both went into overtime. The Knicks took Game 3 111–108, and Los Angeles won Game 4 to re-even the series at two games each. Jerry West's 60-foot heave to send the game to overtime would have won the game as a 3-pointer under modern rules.

New York had the edge in Game 5 until Reed collapsed with a torn leg muscle, allowing Chamberlain a strong advantage. Knicks coach Red Holzman devised a strategy to confuse the Lakers with a centerless lineup, rotating different defenders on Chamberlain. The Knicks went on to win 107–100. With Reed out, Chamberlain scored 45 points in Game 6 in Los Angeles to knot the series again at 3. Game 7 would be in New York, but without Reed, the Knicks appeared to have little chance of winning.

With ABC's Chris Schenkel and Jack Twyman leading speculation about what the Knicks could do to guard Chamberlain, Reed emerged from the locker room and joined his team on the floor, shocking thousands and surprising the Lakers. Energized by their big man's effort, the Knicks roared to an early lead and held on long after Reed limped to the bench. The Knicks achieved sports immortality with the 113–99 victory, their first NBA title.

Reed was lionized for his effort, but it was also Dave DeBusschere's stellar inside play and Walt Frazier's brilliant all-around game that won the game for New York. Chamberlain and West were runners-up again, their outstanding stats and performances again good only for second place.